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Answer:

2

Explanation:

4s2 has 2 valence electrons

Valence shell is the shell which is the outermost shell, that is filled in the last, before valence shell is penultimate shell. Therefore 2 valence electron are there in the valence shell.

Element generally consist of atoms or we can say atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

From our question the electronic configuration of element is given as

1s²2s²2p⁶3s²3p⁶4s²

Valence electron is the one which is present in the outermost shell or orbit. So, form above electronic configuration we can say that 4 is the outermost shell and in this shell 2 electron is present. Therefore 2 electron are there in the valence shell as valence electron.

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Answer:

The enthalpy change of the reaction is 4.78 × 10⁴ J.

Explanation:

We are given that 0.717 g of sodium metal reacts with hydrochloric acid to produce 7450 J of heat.

Converting grams of sodium to moles:

[tex]\displaystyle 0.717 \text{ g Na} \cdot \frac{1 \text{ mol Na}}{22.99 \text{ g Na}} = 0.0312 \text{ mol Na}[/tex]

And dividing the amount of heat produced by the moles of sodium reacted yields:

[tex]\displaystyle \Delta H = \frac{7450 \text{ J}}{0.312 \text{ mol Na}} = 2.39 \times 10^4 \text{ J/mol Na}[/tex]

Because the given reaction has two moles of sodium metal, we can multiply the above value by two to acquire the enthalpy change of the given reaction:

[tex]\displaystyle \Delta H = 2\text{ mol Na}\left(2.39 \times 10^4 \text{ J/mol Na}}\right) = 4.78 \times 10^4 \text{ J}[/tex]

In conclusion, the enthalpy change of the reaction is 4.78 × 10⁴ J.

Numer of moles of Li₂CO₃:

[tex]\longrightarrow\: n_{(Li_2 CO_3)} = \dfrac{38.5}{(6 \times 2) + 12 + (16 \times 3)}[/tex]

[tex]\longrightarrow\: n_{(Li_2 CO_3)} = \dfrac{38.5}{12+ 12 +48}[/tex]

[tex]\longrightarrow\: n_{(Li_2 CO_3)} = \dfrac{38.5}{72}[/tex]

[tex]\longrightarrow\: n_{(Li_2 CO_3)} = 0.53473 \: mol[/tex]

Chemical Reaction:

2 LiOH(s) + CO₂(g) → Li₂CO₃(s) + H₂O(l)

Therefore, applying unitary method:

No. of moles of lithium hydroxide would be required to produce 38.5 g of Li₂CO₃ in the following chemical reaction are 1.03.

Avogadro's number is the number of units in one mole of any substance and equals to 6.02214076 × 10²³. The units can be electrons, atoms, ions, or molecules.

No. of moles is defined as a particular no. of particles that we can calculate with the help of Avogadro’s number.

Mass of a particular product is also find out by stoichiometry of a reaction as per the no. of mole given in the reaction.

Given,

2LiOH(s) + CO₂(g) → Li₂CO₃(s) + H₂O(l)

2 moles of LiOH are required to produce 73.8g Li₂CO₃

0.027 moles of LiOH are required to produce 1g Li₂CO₃

1.03 moles of LiOH are required to produce 38.5 Li₂CO₃

Therefore, No. of moles of lithium hydroxide would be required to produce 38.5 g of Li₂CO₃ in the following chemical reaction are 1.03.

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Answer:

Melting

Explanation:

Ice begins to melt at 0 degrees celsius

Melting is from solid to liquid

Freezing is from liquid to solid

Sublimation is from solid to gas

Deposition is from gas to solid

Answer: adduction of the arm

lateral rotation of the arm

Explanation:

The pH at the equivalence point for the titration of 0.25 M HCOOH versus 0.25 M NaOH is 8.5.

Let's consider the following neutralization reaction.

HCOOH + NaOH ⇒ HCOONa + H₂O

At the equivalence point, 0.25 M HCOOH completely reacted with 0.25 M NaOH to form 0.25 M HCOONa.

HCOONa undergoes hydrolysis. The net ionic equation is:

HCOO⁻(aq) + H₂O(l) ⇄ HCOOH(aq) + OH⁻(aq)

Given the concentration of HCOO⁻ is 0.25 M (Cb) and the basic dissociation constant of HCOO⁻ is 4.8 × 10⁻¹¹ (Kb), we can calculate the concentration of OH⁻ using the following expression.

[tex][OH^{-} ] = \sqrt{Kb \times Cb } = \sqrt{(4.8 \times 10^{-11} ) \times 0.25 } = 3.5 \times 10^{-6} M[/tex]

The pOH of the solution is:

[tex]pOH = -log [OH^{-} ] = -log (3.5 \times 10^{-6} ) = 5.5[/tex]

The pH of the solution is:

[tex]pH = 14 -pOH = 14 -5.5 = 8.5[/tex]

The pH at the equivalence point for the titration of 0.25 M HCOOH versus 0.25 M NaOH is 8.5.

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Answer:

C8H12

Explanation:

First find the molar mass

195/1.8 × 1 = 108.3 gmol-1

Then the molecular formula

Mass of C in 1 mole of compound = 88.82×108.3/100

= 96.2 g

Mass of H in 1 mol of.the compound = 108.3×11.18/100 = 12.11 g

Divide the mass by their molar masses to get no. of moles in 108.3 g of compound or 1 mole of compound

Moles of C in one Mole of compound = 96.2g/12 gmol-1 = 8 mol

Moles of H in 1 mole of compound = 12.11g/1 gmol-1 =12 mol

Since we need the molecular formula it's C8H12

Answer:

447.64 grams

Explanation:

To find the mass when given moles, it is a pretty simple process.

I start by finding the molar mass of chloric acid, which comes out to 84.46 grams/mol. To find the MM (molar mass), you just take the mass of each element in the molecule from the periodic table and add them all together.

After this, you set up the equation by taking the moles given and multiplying it by the molar mass. This gives you the new value in grams (since we cancelled out the moles). I have attached my work below.

I hope this helps! :^)

The mass of 5.3 moles chloric acid has been 447.85 g.

The mass of 1 mole of a compound has been equivalent to the molar mass of the compound. The molar mass of a compound has been the sum of the constituent atoms in a formula unit.

The molar mass (mwt) of chloric acid has been given as:

[tex]mwt=m_H\;+\;m_C_l\;+\;(m_O\;\times\;3)[/tex]

By substituting the values for the mass of constituent atoms, the molar mass has been given as:

[tex]mwt=1\;+\;35.5\;+\;16\;\times\;3\\mwt=36.5\;+\;48\\mwt=84.5[/tex]

The molar mass of chloric acid has been 84.5 g/mol.

The mass of 1 mole of chloric acid has been 84.5 g/mol. The mass of 5.3 moles chloric acid has been:

[tex]\rm 1\;mol=84.5\;g\\5.3\;mol=5.3\;\times\;84.5\;g\\5.3\;mol=447.85\;g[/tex]

The mass of 5.3 moles chloric acid has been 447.85 g.

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Answer:

aluminum Zicam iron

Explanation:

Which metals dont react with anything?

Metals like aluminium, iron and zinc do not react either with cold or hot water. But they react with steam to form the metal oxide and

Answer:

How many grams Iron(II) Sulfide in 1 mol? The answer is 87.91. We assume you are converting between grams Iron(II) Sulfide and mole. You can view more details on each measurement unit: molecular weight of Iron(II) Sulfide or mol The molecular formula for Iron(II) Sulfide is FeS. The SI base unit for amount of substance is the mole.

Explanation:

Answer:

The answer for number one is .A

The answer for number two is heat rises

Explanation:

Answer:

Bromine

Mercury

Bromine (symbol Br and atomic number 35) is a reddish-brown liquid, with a melting point of 265.9 K. Mercury (symbol Hg and atomic number 80) is a toxic shiny silvery metal, with a melting point of 234.32 K.

Answer:

Aluminium ions present's in 65.5mL of 0.210

M All 3solution is Given below-:

Answer and Explanation: 1

The first step is to determine the moles of aluminum ions. This utilizes the volume, molar concentration, and subscripts from the chemical formula of aluminum (III) fluoride as shown.

65.5 mL×1 L1000 mL×0.210 mol AlF31 L×1 mol Al3+1 mol AlF3=0.013755 mol Al3+65.5 mL×1 L1000 mL×0.210 mol AlF31 L×1 mol Al3+1 mol AlF3=0.013755 mol Al3+

To calculate for the number of aluminum ions, we use Avogadro's number as shown.

0.013755 mol Al3+×6.022×1023 ions1 mol Al3+=8.28×1021 ions Al3+.

Itz the ans. of collage ok man.

Answer:

m0.013755

m

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l

A

l

3

+

×

6.022

×

10

23

i

o

n

s

1

m

o

l

A

l

3

+

=

8.28

×

10

21

i

o

n

s

A

l

3

+

L

×

1

L

1000

m

L

×

0.210

m

o

l

A

l

F

3

1

L

×

1

m

o

l

A

l

3

+

1

Explanation:

The first step is to determine the moles of aluminum ions. This utilizes the volume, molar concentration, and subscripts from the chemical formula of aluminum (III) fluoride as shown.

65.5. To calculate for the number of aluminum ions, we use Avogadro's number as shown.

Hemoglobin with bound carbon dioxide and hydrogen ions is carried in the blood back to the lungs, where it releases the hydrogen ions and carbon dioxide and rebinds oxygen. Thus, hemoglobin helps to transport hydrogen ions and carbon dioxide in addition to transporting oxygen.

Answer:

34 grams

Explanation:

Assuming m/v means mass of solute / volume of solvent, then set up the equation:

1.7/100=m/2000, by cross multiplication, m=34 grams

Answer:

see explanation

Explanation:

Given 0.100M NaOH + 50ml 0.100M HCl

If 50ml of 0.100M NaOH is added to 50ml 0.100M HCl => pH = 7

if less than 50ml of 0.100M NaOH => pH < 7

if more than 50ml of 0.100M NaOH => pH > 7.

Example:

50ml(0.100M NaOH) + 50ml(0.100MHCl) =>

      0.500mole NaCl + 0.500mole H₂O

In this mix, both NaOH and HCl are converted to NaCl and H₂O and NaOH or HCl are no longer present giving a neutral solution. Since neither Na⁺ nor Cl⁻ undergo hydrolysis, the pH is dependent upon H₂O ⇄ H⁺ + OH⁻ and [H⁺] = [OH⁻] = 10⁻⁷M => pH = -log[H⁺] = -log(10⁻⁷) = -(-7) = 7

If less than 50ml of 0.100M NaOH is added, the mix will have an excess of HCl and the pH will be acidic; i.e., less than 7.

If more than 50ml of 0.100M NaOH is added, the mix will have an excess of NaOH and the pH will be alkaline (basic); i.e., greater than 7.

Answer:

A Option is the correct answer.

Explanation:

will share 2 elctrons with 2 Cl to form

S in column 16 WILL SHARE 2 ELECTRONS WITH 2 /Cl to form

SCl2

,

Answer:

a. carbon    CCl4

b. nitrogen NCl3

c. aluminum AlCl3  

d. sulfur SCl2

Explanation:

10. Based on their valence electrons, how many

atoms of chlorine are expected to bond

with each of the following elements?

a. carbon    CCl4

b. nitrogen NCl3

c. aluminum AlCl3  

d. sulfur SCl2

Cl is in Periodic Table column 17, so it has 7 valence  and needs 1 more to have an electronic structure like its nearest noble gas, Ar.

It then has an oxidation state 0f -1.

Carbon in column  has  +/-4 charge, so 4 Cl will bond with 1 C to make

covalent CCl4

Nitrogen in column 15  is -3.  It will share 3 electrons with 3 Cl to form

covalent NCl3

Al in column 13 give away 3 electrons to 3 Cl to form

ionic AlCl3

S in column 16 will share 2 electrons with 2 Cl and frorm

SCl2

Answer:

more heat

Explanation:

more heat bro , more heat

Explanation:

The answer is given in the question

Answer:

methane and petrol okkkkkkkkkkkkkkkkkkk

Answer:

Westerlies are prevailing winds that blow from the west at midlatitudes. They are fed by polar easterlies and winds from the high-pressure horse latitudes, which sandwich them on either side.Nov 15, C answer

Answer:

it is an endothermic reaction because the system takes energy from the surrounding.

Answer:

It is an endothermic reaction because the system takes energy from the surroundings.

Explanation:

I did the test.

Answer:

6.02 × 1023

The molar mass from the periodic table is 32.00 g O2 = 1 mol O2, and by definition, 1 mol O2 = 6.02 × 1023 molecules O2.

Answer:

There are 95 atoms in mercury phosphate

Explanation:

You just add the atomic number for both elements

Answer:

First option

Explanation:

The option that says CH3CH2CH2CH3 is the correct option (I hope that I am right because the order of the answers is not very clear :/)

no I will not please put you because that's the god of the Bible

Metals are good conductors of heat and electricity, and are malleable (they can be hammered into sheets) and ductile (they can be drawn into wire).

Nonmetals are (usually) poor conductors of heat and electricity, and are not malleable or ductile; many of the elemental nonmetals are gases at room temperature, while others are liquids and others are solids. 

The metalloids are intermediate in their properties.  In their physical properties, they are more like the nonmetals, but under certain circumstances, several of them can be made to conduct electricity.

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Answer: It is either C. or D.

Explanation: I did some reading about it and it talks about fuel but I know that it didn’t say all of them are used as fuels.  maybe I’m wrong

Petroleum is composed of hydrocarbons of various chain length. Different products can be extracted from petroleum but all products cannot be used as fuel.

Hydrocarbons in diesel have higher boiling point than that of gasoline.

Petroleum is a naturally occurring crude liquid mixture of hydrocarbons. Petroleum can be fractionated to different components such as gasoline, kerosene, diesel etc.

Each fraction vary in the number of carbons and hydrogens in it or called the difference in chain length. Kerosene contains 8-16 carbons where as gasoline and diesel have more carbons.

Not all products of petroleum fractionation can be used as fuel. Some of them with effective quality is taken as fuels.

The boiling point of hydrocarbons in diesel is greater (about 130-380 degree Celsius) than the hydrocarbons in gasoline which is having boiling point in he range 30-225 degree Celsius.

Therefore, the statement C is correct.

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